4. The solar system is held together by gravity

Newton's Law of Universal Gravitation (NOT the law)

Kepler’s 3rd Law p Jacaranda text

5. The sun is a typical star, emitting electromagnetic radiation and particles that influence the Earth

Interior of the Sun Regions of the sun include the core, radiation zone, convection zone, and photosphere. Gases in the core are about 150 times as dense as water and reach temperatures as high as 16 million °C. The sun’s energy is produced in the core through fusion of hydrogen nuclei into helium. In the radiation zone, electromagnetic radiation flows outwards in the form of heat. The gases in this zone are about as dense as water. The radiation zone is cooler than the core, being at about 2.5 million °C. In the convection zone, churning motions of the gases transfer the sun’s energy outwards. The convection zone is slightly cooler, at about 2 million °C, and less dense, about one-tenth as dense as water. The photosphere is much cooler, about 5,500° C and much less dense, about one-millionth as dense as water. The turbulence of this region is visible from the earth in the form of sunspots, solar flares, and small patches of gas called granules. © Microsoft Corporation. All Rights Reserved.

5. The sun is a typical star, emitting electromagnetic radiation and particles that influence the Earth Sunspots The surface of the sun is shown here in false colours. Sunspots appear yellow, although they would normally appear as dark spots. Sunspots are often larger than 30,000 km and appear in cycles of 11 years. Solar activity, including the development of sunspots, is associated with the sun’s changing magnetic fields. sunspots represent regions of strong magnetic activity and lower temperature When sunspot activity is at a maximum, communication and electricity networks may suffer disruption

5. The sun is a typical star, emitting electromagnetic radiation and particles that influence the Earth The solar wind carries with it a magnetic field whose strength and orientation are determined by activity and features close to the Sun’s surface. Interactions between this interplanetary magnetic field and that of the Earth in turn influence auroral activity and under some circumstances lead to magnetic storms. © Microsoft Corporation. All rights reserved. Coronal plasma within one or two radii from the Sun’s surface is trapped by magnetic field loops. At greater distances, however, the plasma has sufficient kinetic energy to overcome this magnetic restraint, and escapes into interplanetary space. The resulting outward flow of the Sun’s atmospheric plasma is called the solar wind.

Geophysicists believe that convection currents of charged, molten metal circulating in the earth’s core are the source of the magnetic field. 6. The conditions at the surface of the Earth are influenced by the interactions between physical phenomena generated by both the sun and the Earth The internal structure and composition of the Earth produce a magnetic field protecting the Earth from excessive ionising radiation The Earth’s magnetic field traps protons and electrons (in the solar wind) from space in the form of Van Allen belts. These are 2 doughnut-shaped regions that ring the Earth. The charged particles spiral along the magnetic field lines and may enter the Earth’s atmosphere near the poles to cause auroras. The Earth’s magnetic field also deflects dangerous ionising radiation.

In the stratosphere, ozone is formed and creates a layer that protects the Earth's surface from excessive ultraviolet radiation. Outline the composition of the atmosphere and its effect on the penetration of electromagnetic radiation Define black bodies in terms of the heat radiated and absorbed and compare the Earth to a black body The atmosphere traps heat from the sun (infra-red radiation), providing a suitable temperature for survival of organisms. The Earth’s atmosphere consists mostly of Nitrogen (78%) and Oxygen (21%). Other gases include Argon, Carbon Dioxide, Neon, Helium, Methane, Krypton and water vapour. The troposphere is the densest part of the atmosphere and is where we live. ‘space’ begins here These layers may also be referred to as the ‘ionosphere’ and contain many ions and free electrons caused by radiation from the Sun. Gamma rays and X-rays are absorbed by Oxygen and Nitrogen